A highly efficient double-clad Yb<sup>3+</sup> -doped fiber laser with a novel cladding geometry is described. A round double-clad fiber with a small D-shaped hole for breaking a circular symmetry in a cladding combines the advantages of ease of manufacture and handling round fibers with efficient absorption of pump light. Fiber lasers with a double-D cladding shape and a D-hole cladding are compared. We report what are to our knowledge the highest slope efficiencies of 73% and 69%, respectively, pumping at 915 nm. Output powers in excess of 13 W are demonstrated.
© 2003 Optical Society of America
(060.2280) Fiber optics and optical communications : Fiber design and fabrication
(140.3480) Lasers and laser optics : Lasers, diode-pumped
(140.3510) Lasers and laser optics : Lasers, fiber
(140.3570) Lasers and laser optics : Lasers, single-mode
(160.5690) Materials : Rare-earth-doped materials
A. Martínez-Rios, A. N. Starodumov, H. Po, Y. Wang, A. A. Demidov, and X. Li, "Efficient operation of double-clad Yb3+-doped fiber lasers with a novel circular cladding geometry," Opt. Lett. 28, 1642-1644 (2003)